Shows a construction worker standing in concrete at the Hoover Dam construction site. Concrete forms can be seen as well as the huge bucket used to pour concrete into the forms. The bucket was lowered by hoisting machinery,...

Shows the "Train of Tomorrow" at the upstream face of Hoover Dam, where concrete is transferred from trains to the dam. Hoisting machinery, high scaling equipment, and train trestle can be seen. There is a group of people...

A concrete pouring bucket lowers the third millionth yard of concrete used in the construction of Hoover Dam. Cableways, the intake towers under construction, mountains, and construction workers are also visible.

Upstream side of dam showing intake towers that are almost finished. Reservoir (Lake Mead) has begun to fill, and a man is rowing a boat on the lake. There are derrick cranes visible on both sides of the canyon.

Upstream side of Hoover Dam showing the intake towers, which are almost finished. The reservoir (Lake Mead) has begun to fill, and a man is rowing a boat on the lake. There is a wooden walkway laid over piers or...

Shows upstream side of the dam with the almost-finished intake towers. Also shows the mouth of a diversion tunnel and derrick cranes on both sides of the canyon. The reservoir (Lake Mead) has begun to fill.

Shows upstream face of dam with almost-completed intake towers. The reservoir (Lake Mead) has started to fill, and a man is rowing a boat on the lake. The mouth of a diversion tunnel on the left side of the picture...

Concrete pouring forms being put in place for the construction of the Arizona valve house. A construction worker, a hook hanging from a crane, ropes for high scaling, and a ladder attached to the side of the cliff are visible.

Handwritten inscription on back of photo: "Rex motor mixer that has been picked off a white truck and being swung into position at tunnel #1 with load of cement." Shows hoisting machinery, railroad tracks, a steam locomotive, a...